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3 SheetsfSheefc l G. M, BACON COMPUTING MACHINE Filed sept. 9, ,1921

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STATES PATENT orifice.l

GEORGE WI. BACON, OF SALT LAKE CITY, UTAH, ASSIGNOR TO BACON MULTIPLIEH,

TNCORPORATED, OIF SALT LAKE CITY, UTAH, A CORPORATION OF UTAH.

COMPUTING MACHINE. I

Application filed September 9, 1921. Serial No.` 499,451.A

' To all 'whom t may concern:

Be it known that I, GEORGE M. BACON, va

citizen of the United States, and resident of application has been giving satisfactory reintermediatey shafts from the register wheel' tions in the`transfer mechanism associated' CII O sults in operation, it has been found desirableto improve the construction in various details in order to `facilitate assembling the machine more readily and to simplify and improve the construction, and thereby `re duce friction and improve the action.

Iii the register wheel and transfer mechanism shown and described in my prior application, the line of shafts leading to the .register wheels comprises an intermediate section rotatably supported in axial alignment with two other shafts including the registeruwheel shafts and a .clutch mechanism was interposed for disconnecting the shafts for returning the register Wheels to zero. The, thrust of the spring for the Yclutch and the lack of rigidity in the jointed shafts not onlycomplicate the mechanism,

but increased the friction in the machine.

'.Furthermore, in the construction shown in the prior application, the gear conneceliminated and the register wheel and driv ing shafts are made up'of but two shafts both of which are supported in ample bearings so 'that greater rigidity is secured and, as previously stated, the various gears and pinions making up the driving connections between the two sections of the shafts, and

forming the interconnected transfer mechamsm, lhave been so designed that those used inthe total products unit are substantiallyv -di'iplicates of those used in the products unit.

As shown and described' my application, above referred to, the register wheels f are rotated twice for each rotation of the driving shafts, operatedby the dierential gears, and intermediate planetary pinions and gears are utilized for connecting the two shafts together and giving the required 4difference in speed of rotation. The rela` tive size of the gears and pinions making up the planetary gears for doublingthe speedv of rotation of the register wheel may be varied more or less, but it is vvvell known that the best results may be obtained when the meshing gears are more y'nearly the same size. There will be less friction and less lateral thrust than would be the case with a large gear driving a small pinion.'

Therefore, one object of my present imp rovement is to so, proportion the pitch and diameter of the intermeshing gears and pinions as to reduce to a minimum the friction and thrust which might affect the case of operation or life ofthe machine. In this case, it has been found that for the best results the ideal relation between the intermediate gears and pinions should bein the ratio of the square root of two to one. "It is .somewhat diiiicult` to obtainthis exact ratio, but by a proper selection of the pitch .and number of teeth, I have worked out a very close approximationl to the ideal ratio above referred'to.

In improved multiplying machine, alternateregister wheels or dials of-,both the products and total products units rotate in opposite directions and in my prior application, themecha-nism shown for restoring the dials to zero comprise multilated pinions and two oppositely disposed mutilated racks for cooperation with the mutilated pinions for rotating adjacent register wheel dials in opposite directions when. restoring them to Zero. Another object, therefore, of my improved construction, is to simplify this mechanism and provide for separating ,represents a vertical the interconnected transfer gearing so that all of the register wheel shafts he rotated in the same direction for restoring them to zero, thus recpiiring,1 hut a single mutilated raclr for cooperation with the mutilated gears. 'lhis improved construction further eliminates the necessity for rotating, the clearing pull and improves and simplifies' the construction as well as requir-` ing1 less power and rendering the operation more uniform.

ln accomplishing this feature of my im proved machine, it will he noted that a parH ticularly novel construction has been devised in which a separation of the interconnected 'transfer gearing is accomplished by simule taneously moving all of the multi-toothed Geneva wheels out of operative relation with the single toothed Geneva members., so that both may be rotated independently in restoring the register wheels to zero.

Another feature of my present improvement relates to means for preventingoverthrow of the register wheels when return# ing them to Zero. lt is ohvious that when restoring the register wheels to zero, the speed or rotation of the register wheels may he considerable and the inertia may cause the wheels to overthrow after the rack lreaches the flattened or mutilated portion of the respective pinions. To obviate this ohjcction, l have in my present improvement, devised a simple and novel mechanism for preventing such (wertnrow` of the register wheels and for accurately stopping,` them at the zero point.

The accompanying drawings will serve to illustrate the details of my present improvements and only such parts et the complete -machine as are necessary to properly show the improvement are he're shown, for reference may be had to the complete showing of the machine in my prior application, Ser. No. 429,107, hereinbefore referred to.

In the accompanying drawings, llig. l longitudinal section through the products dials and also through the total products dials; lig. 2 isa transverse broken section, substantially on the line 2-2 of Fig. 3; showing the movable frame carrying the Geneva wheels; Fig. 3 is a front view partially in section showing the clearing pull bar; Fig'. 4 is an enlarged view' of the ditlercntial gearing,` of the product dials, looking` toward the front from the line 4 4 of Fig. l; Fig. 5 shows the Geneva single toothed member and the associated Geneva wheel of one of the total product register wheels, the view being taken on the line 5 5 of Fig. l; Fig. 6 is a vertical transverse broken section, showing,` parts of the gear mechanism of the total products dials; Fig. 7 is a hrolten transverse vertical section showing details of the mechanism of the products dials; Fig. 8 is a sectional detail .mechanism are substantially duplicated suhstantially on the line showing the clearing,r` raclr t nism for pinventing.;v overthrow storing the register wheels to zere, a 9 is a top plan view of the mechanism o, Fig. 8, and also shows the clearing Referring 'to the drawin s, and par sich: larly to l thereof, it will he seen the product register wheels and trans the total products register wheels and ticasfer mechanism and, therefore, it will no necessary to fully describe the two units rately. 'lhe mechanism will he descrihe i connection with the products dials oi ter wheels and the corresponding paru,` the'total products unit will he gvcn saine number, with the exponent a From lig. l, it will he seen that the gear mechanism of the products register 't' may be assembled and mounted as a unit, mechanism supper between angle o c l and '2, which entend transversely oi -n machine and may he secured to the sin. plates thereof hy screws or otherwise, a may he desired.. 1 Each products register Awheel or dial 3 is secured to 'the forward end of the shaft 4,-which is supported in a. transversely extending,l plate or bar 5,' ls shown in l of the drawings The shaft 4 passes rearward through the angle plate l, and has a hearing therein 'lhe rear end of the shaft 4 6 is turned down and enters a socket in the forward end of the driving shaft 7 which passes through and lfm has a hearing in the angle plate 2.y The rear end of the shaft 7 may be supported in the bearing brackets of the diiferential wheels, substantially as shown in my prior application, No. 429,107, liereinhefore referred to, lt will thus he seen that the two shafts 4 and 7 are in axial alignment and both rigidly supported, so that there is little likelihood of cramping or disarrangement of the cooperating mechanisms.,

The shaft 7, at its rea-r end carries the pinion S, which is slidably mounted thereon and adapted to mesh with' the differential gears when slid longitudinally of the shaft, as shown in my prior application. Preferably, the pinion 8 is secured to the end of a tubular barrel 9, provided with longitudinal slots l0, cooperating` with a pin ll, extending through the shaft 7 into the slots l0, as indicated in Fig. l of the drawings. In this manner the sliding,- connections hetween the shaft 7 and the pinion 8 is placed lill at a `greater distance from the axis of the `and holding the pinion 8 in proper meshing relation with the'diiferentia] wheels, as

shown and described inmy prior applicav tion. The'lever arm 15 carrying the roller 16, which operates in the annular groove 13 is provided for` selectively positioning the pinion .8, according to the multiplicand digits, as shown and describedin my prior application.

The rotation of the driving shaft 7 is communicated both to the products dials and to the total products dials and forlthis purpose, the inner end of the shaft is provided with a gear 17, which may preferably be connected by a tubular shaft or hub 18 with a spur gear 19the two gears in the products i unit being secured to the shaft 7 by a pin 20,

as seen in Fig. 1 of the drawings. The gear 19 meshes with' the corresponding gear 19a, of the totalproducts unit which through the tubular shaft or hub 18a rotates the corresponding gear 17a, (see Fig. 1). The gear 17 meshes with a pinion 21 secured to or integral with a gear 22, both rotatably mounted on a pin or stud 23, secured to and projecting laterally from a large spur gear 24, which is rotatably mounted upon the shaft 4. Between the large spur gear 24 and the gear 17 a pinion 25 is mounted upon the endl the large gea-r 24 kat diametrically opposite points, as will be seen from the drawings.

'As previously indicated, small intermeshing planetary gears of this type, should be properly proportioned, in order to obtain the best operating results. -In my machine, the

relation between the interconnecting gears between the shafts 4 and 7 Aare so related that the shafts 4, carrying the register wheels or product dials, are rotated twice for each rotation of the driving shafts 7, or of the tubular shaft 18` and gear 19, which corresponds with the similar parts 18L and 19a of the total product dials.

Ihave found by careful calculation and experiment that vfor back gearingy of this character, in which the shaft 4 is rotated twice for each rotation of the shaft 7, the ideal ratio between the intermeshing gears and pinions should be approximately `as the square root of two to one. In utilizing standard pitch gears, it is somewhat diiiicult to obtain this exact ratio, nevertheless, I.

have worked out a very close approximation thereto by making the gears substantially as follows :--'I`he gears 17 are forty-two pitch with twenty-four teeth and mesh with the pinions 21, which are of forty-two pitch with eighteen teeth. The gears 22, which rotate with the pinions 21 are of forty pitch with twenty-four teeth and drive the pinions 25, which are of forty pitch with1 sixteen teeth. It is found' that'these relations approximate very closely to the ideal ratio above indicated and so split up vor divided the work of each gear and pinion, that the wear and friction is reduced to a minimum, while, at the same time, the proper relations are maintained between .centers ofthe various gears and pinions.

The large gears 24, .which support the planetary pinions 2 1 and 22 are rotatably mounted upon the shaftsv4, but are ordinarily held against rotation by the engagement therewith of pinions 27, secured to shafts 23, which shaftsv also carry vthe Geneva wheels 29'. The latter, in the present instance, are provided with four teeth or' operating notches for cooperation with the single tooth Geneva members 30, which are secured to the shafts 4 by means ofthe pins 31, as will bel seen in Fig.,1 of the drawings. `The Geneva members 30 are provided withlaterally projecting annular flanges32, which cooperatewith the dwell portions of the Geneva wheels 29,l thereby preventing. rotation of the pinions 27 and theassociated large gears 24, except where the flanges 32 are interrupted and the single operating tooth or pin 33 is provided, as indicated in Figs. 5 and 7 of the drawings.

It. will be observed that the construction and interconnection of the register wheels and transfer mechanism, so far as the mode of operation is concerned, is substantially identical with that described in my pending application hereinbefore referred to. However, in the former construction, the corresponding annular flanges 32 were made wider and the single toothed Geneva members 3() were keyed to the shafts and slidably y mounted thereon, so that they could be moved to open `the clutches while the Geneva wheels remained in contact with the flanges 32. This construction permitted the register wheels to be returned to Zero, but it was necessary to rotate adjacent wheels in opposite directions. The presence of the clutches and their springs not only added to the complication of the mechanism but increased the work of operating the machine.

In the present improvement, it is proposed to simplify the construction and reduce the friction as well as rovide for rotating all of the register wheels in the same direction when restoring them to zero. For this purpose, the shafts 28, carrying the pinions 27` and star or Geneva wheels 29, are all rotatably mounted in a separate movable frame, comprising side bars 34 and 35, which may be rigidly secured together by tubular members 36, substantially as indicated in Fig. 2 of the drawings. The frame 34-36 is slidably supported transverselyl of the machine, between the angle plates 1 and 2, by means so that when the traine is moved toward the lelit, as indicated in Figs. 2 rand 8 of the drawings, the Geneva wheels 29 will be moved out et the field of the corresponding single tooth Geneva members 30, while the pinions 27 will move circuinliereiitially of and remain in mesh with the corresponding large gears 2st. ln the normal position,

with the frame MM35-BG toward the right,-

as. indicated in Fig.y 2, the Geneva wheels will be in operative engagement with the corresponding flanges 32 of the Geneva ineinbers 30, so as to be in position to transiter the tens when the 'register wheels are rotated in the ordinary manner. For the purpose of holding it in and returning the traine Sat-35H36 to normal position, a spring il-l is preferably provided` one end of which is secured to a pin 42 projecting from one edge ot the frame bar 34, the opposite end being secured to a pin t3 secured in the trame plate 1, as indicated in Fig. 2 oft the drawings.

Then it is desired to reset the reg# ister wheels or product dials to Zero, this maybe done by simply moving the trame 34-35-36 toward `the lett, as shown in Figs. 2 and 3 ot' the drawings and then rotating the register wheel shafts 4 until the register wheels are brought to Zero. For the purpose o't' restoring the register wheels i to zero, the product dials register is provided with a pull bar 411-, which is provided with a suitable knob or pull, as shown in my previous application, but in thepiesent instance, the bar' tat is merely slidably mounted transversely ot the machine. The bar 14 is provided with a cam projection at 45, adapted to cooperate with the short arm t6 oil a bell-crank lever, pivoted at 47 on angle plate l, the long arm 4S of which projects downward, as indicated in Fig. 3 et the drawings, into position to engage the end of one o't the pins 39 projecting through the plate 1.

For restoring the register wheels to zero', each o't the register wheel shafts 4t is provided with a mutilated pinion 4i) secured to the respective shafts by suitable pins 50, which may project beyond the pinions and are utilized for preventing overthrow of the registerwvheels when restoring them to Zero as will be more particularly described hereina'liter. The pinions i9 are preferably elongated as shown in Fig. l of the drawings,

register wheels to Zero. Gl is provided tor restoring the clearing bar to normal position and 'full stroke mechaoperation with the mutilated pinions to rel store the register wheels to Zero, by reciprocating the rack. The rack 53 is mutilated by removing a .'tew ol the teeth at 54e, so that when the rack is iii the normalposition indicated in Fig. 8, the piiions i9 may be ilfreely rotated with the. register wheels. The

mutilated rack 53 is slidably supported by means ot pin and slot connections between 'the rack and 'liront plate l, in any suitable manner. Preferably a pin 55 at the lett end ot the raclr 53 projects through the elongated horzontal slot 5G in the plate l and through a short slot 57, in the clearing pull rod 4rd,! as indicated in Fig. 9 of the drawings. Tlie end of the pin 55 may be threaded and provided with a nut 58 for holding thel parts in operating relation. A suitable spring, such as shown iii my prior application, may be provided :tor holding the rack 53 .toward the lel't, which'is the normal position, as shown in Figs. S and 9 o'll the drawings. lt has previously been explained that the clearing pull bar il/t, by means ott the cam l5 is adapted to lirst separate the Geneva wheels aiid then the register wheels can be rotated by the rack Yto restore them to Zero. ln order that this may be done, the bar 441, by means olthe short slot 57 is permitted a su'l'licient amount ot' movement for the cam ll5 to operate betere the bar picks up the pin 55 and moves the rack 53.

'lhe clearing pull rod as; is slidably supported by the pin and by means ot a pin or stud 59 operating in a slot 60, as indicated in Fig. 3 ot the drawings, the slot 60 being of sul'licient length to allow for pulling out the rack 53 tar enough to restore the il.. suitable spring nism, such as shown and described in my prior application, may be employed in cennection with the clearing pull it so desired.

has been pointed out that there is a possibility ot overthrow ot the register wheels when the rack 53 reaches the :dat or mutilated portions 52 oit the pinions 49, particularly when the clearing pull is operated at high speed. This is likely to cause reengagement 'of the piiiioiis i9 with the racks and, to avoid this, it is desiiable to provide suitable means for preventing overthrow.

lOl)

In the present instance, this is accomplished in a simple manner by providing the radially extending pins 50,l which are so placed as to rotate immediately back of and outv of the field of the rack 53. For cooperation with the pins 50, when restoring the register wheels to zero, a notched plate 62 is slidably mounted between the rack 53 and a retaining plate 63 which may be secured to the angle plate y1, by means of screws 64, the retaining plate 63 being held 'in proper g spaced relation therefrom, by suitable collars 65 as indicated in FigsjS and 9 of the drawings. The notched plate 62 is provided with slots 66 cooperating with suitable pins 67, projecting from the retaining plate 63. as indicated in Fig. 8 of the drawings. The plate 62 is shown in normal position in Fig.

' 8 of the drawings, and is provided with recient width and depth to permit the free rocesses 68 on the lower edge thereof of suii- 8 and 9 of the drawings, by means o-f a later-y f ally extendinglug 69, secured by a pin or screw 70 to the upper edge of the rack 53, at the left end thereof, the lug 69 being adapted to cooperate with a pin 71 projecting upward from 'thev edge of the plate 62. A spring 7 2 is preferably connected with the pin 71, and to a fixed pin 73, so as to normally urge the plate 62 toward the left, or into position fo-r the plate to intercept the pins 50. Normally the parts will be in the positions shown in Figs. 8 and 9, but it will be understood that when the clearing pull 44 is drawn out to restore the register wheelsto zero, the rack 53 will be moved toward the left and by the time the mutilated rack picks up the teeth of the mutilated pinions 49, the spring 72 will have moved the plate 62 into the field of the pins 50. The movement of the plate 62 under the actionof the spring 72 will be limited by the length of the slot 66 cooperating with the pin 67.-

'As shown and described in myi prior application, the planetary gear mechanism and Geneva wheels are located in two planes so that adjacent mechanisms overlap thereby concentrating the mechanism and getting the register wheels closer together. Both the products and the total products register wheels are arranged in this Amanner and the construction and operation of both sets of wheels and associated mechanisms is subthe only difference stantially identical, being that the relation of the gears is reversed, so that the pinions 49 are at the rear ends of the shafts 4* and the gears 19a and 17a, connected by the tubular shafts 18"', ro-

.tate upon the shafts .4. Suitable spacing collars 74 and 7,4a are provided for properly `spacing the respective vgears on the shafts 4 In the operation of the machine, it will be understood that adjacent shafts 7 are rotated in oppositeA directions, and, therefore, adjacent register wheels in both. the product and total product units are rotated in opposite directions. The transfer of thev tens Ais accomplished bythe Geneva members 30,

operating the respective Geneva wheels 29 each time the corresponding register wheel passes from nine to zero or from. zero to nine. After the product has been obtained, the register wheels maybe cleared by operating the clearing pull bar 44, which, as previously pointed out, first roperates the bell-crank lever 46-48, which moves the Geneva wheel carrying frame -34-35, so as to disconnect the Geneva wheels 29 from the Geneva membersBO, after which the pin. 55 (see Fig. 9)

is picked up by the bar 44, and the clearing` rack 53 is moved ltoward the left. The rack 53 will engage the mutilated pinions 49 of any of the register wheels that are not at zero and rotate them all in the same direction, until the mutilated or flattened portions 52 thereof are brought opposite the teeth of the rack. During the operation the overthrow mechanism comes into operation to prevent the register wheelsv moving beyond the zero positions, this being accomplished by the engagement of the pins 50 with the tongue-like portions of the notched stop plate 62, as previously described.

It is believed that the relation, which I have worked out between the planetary gears and pinions for approximating the ratio of the square `root of two to one is particularly novel andcertainly of very great importance in connection with machines of thisA character, for reducing friction and wear on the parts and, thereby increasing the eiiiciency of operation. It is also .believed that my improved method of separating the interconnecting'transfer' mechanism, is particularly novel, as is also the mechanism for preventing'overthrow of the register wheels when restoring them to zero.

It will be understood, therefore, that in my claims for these improvements, I do not wish to be limited to the specific construction shown and described, for obviously, the details thereof may be modified or varied, without departing from the spirit and scope of the invention.

I claim 1. In a computing machine, *the combination of a plurality of register wheels, interconnected by transfer mechanism comprising planetary gears and Geneva wheels and their actuators, and means 'for simultaneously moving all ot said Geneva wheels out of engagement with the respective actuators While they remain `geared tothe planetary gears.

2. In a computing machine, the combination of a plurality ot register' Wheels and transfer mechanism, including a Geneva ac tuator connected with each register Wheel, a plurality ot Geneva Wheels each geared to the adjacent register Wheel ot'higher denomination and mounted for cooperation with the respective Geneva actuators iior transfer oi the tens and means tor bodily moving all ot' said Geneva wheels out ot operative relation to-the respective Geneva actuators, whereby both the Geneva vvheels and said actuators may be independently rotated while restoring said register wheels to Zero.

The mechanism as claimed in claim :2, in which the respective Geneva wheels are geared through intermediate planetary wears with the res iective register wheels so thatmeach Geneva actuator is adapted to transfer the tens to the register ivheel of next higher denomination, when said Geneva Wheels are in operative relation Wit-h 'the respective actuators, and detents are provided for positioning and holding the respective register Wheels in proper registering positions, both ivhenthe Geneva vvhcels are in and ivhen out o'toperative relation to the Geneva actuators.

4;. In a computing machine, the combination otaplurality oitI register Wheels and transfer mechanisms, the latter including planetary gears, a single toothed Geneva actuator connected with each register wheel, a multi-toothed Geneva wheel cooperating with each of said Geneva actuators and geared respectively to the planetary gearing of higher denomination, a common-i ;trame in which all ot said Geneva, Wheels are mounted and means for moving said 'trame as an incident to restoring said register \vheels to Zero, so as to simultaneously disengage the Geneva Wheels from the Geneva actuators ivhile they remain geared to the respective planetary gearing.

5. The mechanism as claimed in claim et, in which a manually operated pull is pro vided for moving said frame and the Geneva wheels and means is operated by said pull ior restoring said register Wheels to Zero ai'- ter said Geneva Wheels have been disengaged trom the Geneva actuators.

6. In a computing machine of the charac# ter described, the combination of a plurality ot register Wheels, a plurality ot interconnected gears for transferring the tens, means for simultaneouslyT disconnecting corresponding portions ot the respective transfer gears, 4means for restoring said reg ister Wheel to zero when said transfer gears are so disconnected, and a manual pull :tor

operating said disconnecting means and the v restoring means in succession.

7. rlhe mechanism as claimed. in claim C. in which said intermediate transfer gearing includes a Geneva wheel geared to a large gear Which supports planetary gears and the separation olf said transiter gearing is eti'ected in a manner to permit independent rotation of the register wheels and said Geneva Wheels and planetary gears.

8. In a computing machine ot the character described, the combination with a plurality of registering elements and transfer mechanisms, 'ot a single toothed Genera member secured to each register wheel, a corresponding pluralityv oit Geneva Wheels, adapted during the transfer oit the tens to be operated by the respective Gene 'a single toothed members, a movable frame in which all ot said Geneva wheels are mounted, means -for supporting said 't ame and permitting sutlicient movement thereoit to allow for the rotation of said Geneva Wheels independently of the singlev toothed Geneva members, a. clearing pullv tor restoring the register Wheels to Zero and means operative by said clearing pull for moving said frame when said pull is operated 'tor clearine'.

9. rlfhe mechanism as claimed in claim 8, in Which means is provided tor restoring said trame to normal position after the clearing operation ot said pull With said Geneva Wheels and Geneva members in engagement and for holding them in such engagement during normal operation.

10. In a computing machine of the character described, the combination of a plu rality of register Wheels and interconnected transfer mechanism, the latter being made separable, a corresponding plurality of mutilated pinions connected iv/ith the respective register Wheels for rffstoring'them to Zero, a single mutilated lack for cooperation with said pinions, means tor preventing overthrow ot' said register Wheels when the mutilated portions ot said pinions come opposite the rack and the register Wheels are at zero, and a clearing pull for separating the separable portions of the transiter meclr anisms and for operating said rack after the separation talzes place.

1l. In a computing machine of the chan acter described, the combination with if ter Wheels and transfer mechanisms, c nui- .tilated pinions connected With the i L ctive register wheels, a single mutilated 'f c for cooperation with saidpinions t, storing the register Wheels to Zero, stop plate under the control ot said and a plurality ci? stop members asso With 'the respective register Wheels adapted to cooperate with said stop p, for preventing overthrow of the Wheels when returned to zero by said l2. The mechanism as :in

MJS

11, in which a'lclearing pull is provided Jr'or operating said rack to restore theregister Wheels to zero and said stop plate is brought into position to intercept said stop members only when, said pull is operated .to move said rack.

13. In a computing machine of the character described, the combination with reg' ister Wheels and transfer mechanism, of-

direction to restore the register Wheels to zero, a corresponding plurality of stop mem-- bers secured to the respective vregister Wheels and pinions, a stop plate held normally out of the eld of said stop members but adapted to be moved intothe field thereof when said rack is operated,`means for moving said rack and independent means for lmoving said stop plate when said rack is moved.

T14. The mechanism -as` claimed'in claim 13, in which a .manually operated clearing pull is providedfor operating said rack,

.and a spring is adapted to move said stop' plate in a direction to place it in the'field of v said stop members, said rack being provided with a lug'engaging said plate for moving itin the opposite direction to restore it to normal position out of .the field of said stop members.` f

GEORGE M. BACON. 

